Third-party apps can make or break a phone platform -- one of the great strengths of the iPhone is the huge number of "long tail" apps that let users personalize their phones and extend their functionality.

Microsoft has reportedly paid developers of popular apps like Netflix and Facebook to create versions for Windows Phone, but smaller developers don't get any such treatment, and with the tiny Windows Phone installed base so far, there's little incentive for them to port their apps to the platform.

Worse, developers have also had to deal with some tight restrictions on what their apps can and cannot do.

Microsoft is trying to be friendlier to developers with Windows Phone 7.5, or "Mango," which will be a free update to all Windows Phones this fall. The company has released a set of new tools for developers today so they can start building apps for the new version of Windows Phone now.

New features for developers include:

More direct access to phone hardware like the camera, compass, and gyroscope

Access to contacts and calendar

Background processing, meaning an app can continue to do work in the background while the user has other apps open

A local version of Microsoft's SQL database so apps can store structured data

Microsoft is also introducing a Web-based version of the Windows Phone Marketplace, which will make it easier for users to find and buy apps -- today they have to buy them from their phone or the Zune software client (which is also used to sync music, videos, and photos).